Dipper and Mabel's Sleepover
by Rotten Pines
Summary: Set one month after the events of Pacifica's Sleepover, Dipper and Mabel plan another night alone with Pacifica, but first, the twins need to talk about certain events still left unresolved. What will they discover, and how will Pacifica react? (Contains Dipcifica, Mabifica and a LOT of Pinecest. NSFW. You have been warned!)
1. Chapter 1

Chapter 1

It had been one month since that amazing, life-changing sleepover at Pacifica's house. So much had changed in so little time. After getting permission from their parents, Dipper and Mabel began the tedious task of transferring to Gravity Falls High School. Normally, transferring to a new school in your senior year would be an arduous and annoying task, but considering the twins' stellar grades and equally stellar reputation in the community, the school was more than happy to accept them and approve their transcripts as quickly as possible. Now, all Dipper and Mabel had to do was find proper housing somewhere in town.

"Hmm, this place looks nice." Dipper said, pouring over realty listings. "Oh, but this one has it's own washer and dryer."

Dipper had been searching for a new place for himself, his sister and Pacifica for weeks now. Sure, the Mystery Shack was nice, and for several summers had been the twins' home away from home, but if the two were going to live in Gravity Falls year-round, they were going to need more space, somewhere they could stretch out and grow.

There was also the more obvious reason.

In the month since Dipper and Mabel decided to "share" Pacifica, the trio had found it difficult to find a moment of privacy in order to do some actual "sharing." Once Pacifica's parents returned from their trip, her house was pretty much off limits, and the Mystery Shack, with it's paper-thin walls and creaky floors, made it difficult for the young lovers to . . . enjoy themselves without arousing suspicion One time, the trio even tried fooling around out in the woods, only to run into Wendy and her friends, who were thankfully so loud and rambunctious that the three were able to get their clothes back on before being discovered.

The thing was, while Dipper and Mabel were completely, over-the-moon in love with Pacifica, and vice-versa, they knew the rest of the town probably wouldn't approve of their avaunt-guard lifestyle. (Well, Stan probably would, but that's a bit of a red flag right there.) So, for the time being, they agreed to keep everything hush-hush, which meant finding a new place was essential Not only for themselves, but for their poor, restless libidos.

Thankfully, however, they had the night to themselves. Soos and Melody were away at a FCLORP convention, and Wendy, who was supposed to watch the Shack while the two were gone . . . didn't feel like it. Dipper and Mabel saw their opportunity, and invited Pacifica over for another sleepover. So, finally, after weeks of waiting, the three lovers would finally get a little bit of much needed private time.

Of course, Dipper, always looking ahead, was too busy looking at houses to care about anything else at the moment.

"What do you think about this one, Mab– ?"

"FOUR!"

Dipper ducked just as a rogue golf ball went whizzing by his head and out a nearby window.

"What the heck are you doing!?" Dipper shouted.

"Check it out! I've got this really great idea." Mabel beamed, holding a golf club in one hand and a piece of Hot Wheels track in another. "You know how sometimes, at fancy parties, you see sushi being served on top of a naked woman?"

"I don't know what fancy parties you've been to, but go on," replied Dipper.

"Well, I figured we'd do the same thing, only instead of sushi, we make a mini-golf course."

"Wait . . . Let me get this straight," Dipper said quizzically "You want to take those Hot Wheels tracks, and –"

"Strip Pacifica down, lay the tracks over her naked body, and play her like a par 3 at the Royal Discount Putt Hutt." Mabel smiled innocently as Dipper stood there, shocked and confused.

"Why does she have to be naked?" asked Dipper.

"Why shouldn't she be?" replied Mabel, practicing her swing.

"O-okay," said Dipper. "So, where exactly would you . . . put the hole?"

"What?"

"The hole." Dipper mimed a hole with his hands. "I mean, where exactly . . . you're not going to put it in her– ?"

"Oh, get your mind out of the gutter, twin brother!"

"Says the girl who wants to shoot golf balls up her girlfriend's–"

"Look," Mabel sighed. "The track would run up between her legs, past her belly, and over her breasts, before splitting off in three directions. That way, the ball could veer left, down one arm, veer right, down the other, or, if done correctly, go up and over her chin, past her head and into the cup. Simple as that!"

"Simple?" Dipper asked before shaking his head. "Wait-a-minute, aren't you and Pacifica, like, golf rivals or something? If you're going to use her as a golf course, how is she going to actually play?"

Mabel paused for a second. "Oh! Good point," she replied, twirling the golf club in her hand. "Okay, new plan! Me and Pacifica will play mini-golf and you can be the–"

"No."

"But Dipper–"

"No way."

"But Dipper, please–"

"I'm not letting you shoot golf balls up my crotch!" Dipper yelled before covering his mouth out of fear of eavesdroppers. "Now, would you knock it off and come over here. I think I found a good listing for a new place."

"Well, why didn't you say so?" exclaimed Mabel, tossing the club to one side. "Let me see."

Mabel looked down at the listing in the paper, a medium-sized home located just off the main road into town, close to the high school, but still far enough out of the way to ensure a little . . . privacy.

"Hmm . . . It looks nice, but don't you think it's a bit pricey for a two bedroom?"

"Three."

"What?"

"A three bedroom, Dipper replied. "You, me and Pacifica."

Mabel was surprised. "I know Pacifica asked for her own room, but I figured you and I would, you know, share a room, like we always do."

Dipper began to squirm in his seat. His hands twitched. His eyes darted around the room.

"Yeah, but don't you think it's time we finally got separate rooms?" Dipper spoke. "I mean, we've been sharing a room since, like, forever."

"Exactly," said Mabel. "We've been sharing a room since, like, forever. Why do you want to change that?"

"I just think, in light of recent . . . developments, we might need a bit of . . . distance."

"Distance?" Mabel laughed. "Bro, we banged the same chick, at the same time! I think that ship has sailed. Now, what is this really about?"

Dipper sighed. "Never mind. Just . . . forget it."

The boy turned back to the newspaper laying on top of his bed.

"I'll keep looking for a place that–"

"Is this because we kissed?"

" . . . "

It was as if all the air had be sucked from the room. A painful, deafening silence washed over the twin siblings as the words hung in the air. Out of all the events from that night, there was one that perpetually gnawed away at Dipper. A single moment, laughed off as nothing at first, but that one taboo kept him wide awake at night. That single moment opened up a Pandora's box of emotions that Dipper had tried so desperately to contain, tried so desperately to shut the lid on, but with just a couple of words, Mabel tore the lid off it's hinges and spilled it's contents all over the floor.

Finally, after what seemed like eternity, Mabel spoke.

"I know we never really talked about it."

"There's nothing to talk about. It was an accident."

"An accident!?" Mabel shouted. "If that's the case, why are you acting so– ?"

"Look, I didn't mean–" Dipper fumbled. "I just meant that we didn't intend for it to happen, and we shouldn't, you know, read too much into it."

"Says the conspiracy theorist who spent his first summer here literally reading into everything about this town!"

"We both agreed to share Pacifica." Dipper countered. "We never said anything about us."

"So what?" replied Mabel. "You're just going to lock yourself away from me?"

"That's not what I'm trying to do."

"Then what is it!?" Mabel shouted. "Just tell me what–"

"I DON'T WANT TO HURT YOU, MABEL!"

Dipper's echoing voice gave way to . . . nothing as the two stood in silence.

"You are my twin sister. You have been a part of me since before I was even born. Out of anyone in the entire world, you are the one person I love the most; the one person I would protect above all others. This relationship; you, me and Pacifica; it's taboo enough as it is. If the town, or anyone for that matter, found out about it, it would–" Dipper sighed. "I just don't want to make things worse by giving into these . . . desires."

"Then, you do feel something for me?" Mabel responded.

"How I feel doesn't matter."

"It matters to me, Dipper! The whole point of all this is that we be open with one another. You, me, Pacifica; we need to be honest with our feelings, not try to bottle them away and hope for the best. Hell, I spent over a year in the closet, and it was agony. I never want to go back to that again. If you're feeling that way now, then I want to do everything I can to help you. You're my twin brother, Dipper. Just like you said, out of anyone in the entire world, you are the person I love the most."

Dipper sighed. "What if this isn't that kind of love?"

"What do you mean?"

"What if my wires are crossed, and I'm just mixing up my love for you as my sister for, you know, actual romantic love? When we kissed . . . it was in the heat of the moment, and what I felt was so intense, but what if that's all it was; the moment?

"How would we ever be sure?"

Mabel thought back on that moment, a romantic, lustful three-way between her, her brother and Pacifica. She remembered the feeling of euphoria as the two siblings used Pacifica's body for their own pleasure. She remembered the look of longing in her brother's eyes as the two inched closer together, culminating in a kiss that triggered an earth-shattering climax which, to this day, had never been matched in intensity. She had felt it's power, but even she didn't know what it really meant.

There was only one way to be sure.

"Kiss me again."

"What?"

"You heard me. Kiss me again. It's the only way to be sure." Mabel spoke. "Kiss me, and you'll know how you truly feel. There's no Pacifica here; no other distractions. It's just you and me. Kiss me, and we'll finally know where we stand."

Dipper shook his head, partly in protest, partly out of shock.

"But . . . what if I kiss you, and it's nothing?"

 _Worse_ , Dipper thought to himself, _What if I kiss you . . . and it's . . . everything?_

"No matter what, you are my brother, and I love you," replied Mabel. "Nothing could ever change that. The only thing that would change is how we define that love, and trust me, anything is better than not knowing."

Dipper stood there, unsure of what to do, until finally, with a single, deep breath, he began to move.

"I don't want to hurt you." Dipper said, inching closer.

"You won't," said Mabel, taking a step forward.

Dipper placed his hand behind his sister's head, pulling her in to a tight embrace.

"Last chance." He warned.

Mabel closed her eyes, her lips parted.

"Do it."

With that, the two pressed their lips together as the world around them seemed to simply . . . dissolve. It was as if the old, creaky walls of the Mystery Shack pealed away to reveal a wondrous world of light and color, of emotion and serenity, of passion, and, above all, clarity. In that one, glorious moment, everything became so clear, so . . . obvious, and for that one, all-too-brief moment, they knew. They understood.

It was all so simple.

"I love you, Mabel."

"I love you, too, Dipper."

The two looked deep into each others' eyes as they stood in near silence; the only noise being the sound of both their hearts beating in sync with one another, a wondrous, continuous rhythm . . .

. . . that was suddenly broken by a loud thud!

Standing in the doorway was Pacifica, dropping her bags on the floor as her hands moved to cover her mouth, gasping in shock at the scene before her.


	2. Chapter 2

Chapter 2

Do you know that moment when you've run out of excuses? Have you ever found yourself completely exposed, vulnerable and with no other options except for maybe hurling yourself out the nearest window? Have you ever been caught with your hands, or, in this case, tongue, thrust firmly in the proverbial, or incestuous, cookie jar? What runs through your head in those moments? Does time slow down? Does your heart race? Do your arms go numb as your legs turn to jelly?

For Dipper, it was all of that . . . and more.

His limbs suddenly became so weak, he could barely support the weight of his twin sister, who stood there, clutched firmly in his embrace, so closely, in fact, that they were still connected by the loose strands of her hair that clung haphazardly to the side of his face, a symbol of their devotion, and evidence of their sin.

"Oh. My. God!" Pacifica gasped.

"Pacifica!" Mabel choked, her body racked with guilt over betraying her friend and lover. "We didn't mean to–"

"I can not believe this!" The heiress shouted.

"Pacifica, I . . . We can explain!" Dipper fumbled.

"This is just so . . . just so . . ." Pacifica rambled.

"Pacifica, we're sorry!" Mabel cried.

"It's just so . . . FUCKING HOT!"

" . . . say whaaa?"

"I mean . . . Holy Shit!" Pacifica exclaimed. "I knew you two had a thing, but I didn't think you'd have the stones to actually . . . you know! This is so great!"

"A thing? Wait! Seriously, you're okay with this?" asked Mabel. "Jeez! I mean, I knew you were kinky, Pacifica, but I didn't know you were this kinky."

"Ha! Says the girl I just caught playing tonsil-hockey with her own brother!" Pacifica replied.

"Pacifica . . ." Dipper cried out, trying desperately to regain his composure. "We're not–"

"How long?" She asked gleefully.

"How long . . . What?" asked Dipper.

"How long have you two been fucking behind my back?"

"What! No, no!" Dipper recoiled, finally releasing his grip on Mabel. "Pacifica, I swear, we haven't done anything like that!"

"Well, not yet, anyway."

"MABEL!"

"What?" The Pines sister laughed. "It's not like it isn't going to happen eventually." Mabel cracked a mischievous grin. "You and I both felt it, Dipper. You even said it yourself." She wrapped her arms around her brother.

"You love me."

"I . . ." Dipper panicked. "I think maybe I should go."

Dipper turned to leave, but Mabel refused to let go.

"Oh, no you don't, bro!" Mabel shouted. "You are not shutting down on me, again! Not after everything we've gone through to get to this moment."

"Okay, what the hell is going on here?" Pacifica asked. "Are you two fooling around or not?"

Mabel sighed. "Remember the first night we all had sex?"

"Vividly," the heiress beamed. "Go on."

"Well, right before . . . everything came to an end, me and Dipper locked lips, and ever since then, there's been some tension between us. So, I figured we should kiss again in order to see if there was anything there."

"Was there anything there?"

"Totally."

"Nice." Pacifica purred. "Wait, so you two kissed right as you both . . . Does that mean you two kissing is what got you off that night?"

"Oh God! I do NOT want to talk about this!" Dipper stomped around, his face hot with embarrassment "Can we please just STOP!"

"What's wrong, Dipper?" asked Mabel. "You heard Pacifica. She's fine with it."

"BUT, I'M NOT!" The young man yelled at his confused sister as the room went silent.

"Dipper . . . ?"

"I just . . . this is all happening so fast, and . . . I'm afraid." The young man confessed. "I'm afraid that . . . when all is said and done, we'll end up regretting this, and I don't want that kind of guilt to ruin our relationship."

"Oh, Dipper," Pacifica cried as she ran over to her man, wrapping her arms around him. "Look, I'm sorry. I rushed into things just now. I didn't realize how sensitive all of this was for you." Pacifica pulled him into a gentle kiss. "No matter what happens, we love you, and whatever you need, we'll be there to help you. Isn't that right Mabel?"

"Of course," said Mabel, joining the embrace. "Whatever it takes to help you adjust to . . . all this; however much time you need, we're both here for you."

"Thanks, girls." Dipper smiled. "I just . . . I just wish there was a way I could . . . you know, be with Mabel without feeling so guilty about it."

Just like that, it hit her! It was as if a light bulb went off in Mabel's head. Suddenly, she began to smile, then chuckle, before bursting out in a cackling laugh."

"Umm . . . Mabel? Are you okay?"

"Oh, I'm better than okay. In fact, I think I just had the best idea ever!

. . . . .

"Mabel, are you sure this is a good idea?" Dipper asked as he helped drag the heavy load up the stairs.

"All of my ideas are good ideas!" Mabel responded enthusiastically

"Really? Even that time you bedazzled your own face?"

"Hey, it worked, didn't it?" Mabel struggled as she and her brother hauled their cargo through the attic doorway before dropping it onto the floor.

"Alright, I think I waited long enough." Pacifica said as she lounged on Mabel's bed. "Do you mind explaining what your plan is, Mabel?'

"I would love to, Pacifica." Mabel threw her head back, wiping the sweat from her brow.

"Behold!"

With that, the excited teen unfurled the thick shag carpet onto the floor, light blue in color with a yellow circle in the center. Inside the circle were two arching arrows running counterclockwise, and in the corner of the carpet, a small tag bearing the words "Experiment 78."

"Wow . . . A tacky blue rug," Pacifica said sarcastically, "so worth the wait."

Dipper sighed. "It's one of Uncle Ford's old experiments: The Electron Carpet."

"Yep," Mabel beamed. "All we have to do is step on this rug, zap each other with a little static electricity, and BOOM! Body switching!"

Pacifica's eyes went wide. "Are you serious? This thing can actually switch our bodies?"

"That's right!" Mabel smiled. "I figure the easiest way for Dipper to work through the issues with our relationship is to ease him into it."

"So, the two of us switch bodies . . ." Pacifica started, "and then . . ."

"And then you can make love to him in my body!" Mabel grinned. "That way, he can be with me guilt free because he knows it's really you in there."

The looks on Dipper and Pacifica's faces were priceless; a mix of shock and confusion. You could practically hear the gears turning in their heads as they tried to process the information.

"Mabel, I . . ." Dipper started.

"Look bro, you need this, and don't you dare tell me that the thought of plowing Pacifica in my body doesn't turn you on. I can clearly see the bulge growing in your pants."

Dipper blushed, trying desperately to cover himself. "That's not what I mean. It's just thought . . ."

"I think what Dipper is trying to say," Pacifica interrupted, "is that, if we really want to ease him into this, it might make more sense for you to make love to Dipper in my body first . . . God that's a sentence I never thought I'd say."

"No way, Pacifica!" Mabel replied, taking the rich girl's hand. "If, or rather, when Dipper and I make love for the first time, I want it to be in my body, but I'm more than happy to rent it out to you for a bit so my bro can . . . work out his frustrations."

"Mabel . . ." replied Pacifica, "I don't know . . ."

"Too late! You're on the rug!"

Pacifica looked down to find that, indeed, Mabel had pulled the young heiress onto the shag carpet, their feet shuffling on the fuzzy blue fabric, surging with static electricity.

"Mabel, No!" Pacifica shouted.

"Mabel, Yes!" The Pines girl exclaimed as she tapped her friend with the tip of her index finger, setting off a massive flash, bathing the entire room in a bright light, which nearly blinded poor Dipper. In a matter of seconds, the light faded, leaving the two girls slightly dazed in the middle of the room.

"Mabel? Pacifica?" asked Dipper. "Are you two okay?"

The two girls looked down at their bodies, carefully exploring their hands, legs and chest until, finally, an ecstatic squeal came out of Pacifica's mouth.

Except, it wasn't Pacifica.

"This is awesome!" Mabel squealed as she felt up her new body. "These boobs are huge, and her ass is amazing! This really was the best idea ever!"

"Speak for yourself!" Pacifica sighed, pulling at Mabel's colorful outfit. "These clothes are so– Ow! What the– ?" Pacifica winced as she peeked under Mabel's sweater.

"Um . . . Mabel, what is . . . did you bedazzle your bra?"

"Oh . . . uh . . . maybe?" Mabel laughed, "but don't worry. You won't be wearing it for long."

"What? Oh!" Pacifica smirked as she turned to Dipper, his face beet red and a visible tent in his pants.

"You're up . . . Shooting Star!" Mabel laughed as she pushed Pacifica towards her brother, admiring her own ass in the process. For all it was worth, Dipper stood dumbfounded at the sight in front of him. She may have had his sister's face and body, but the fire in her eyes and the sway of her hips was all Pacifica.

"So, are you ready for this, Dipper?"

"Umm . . . I–" Dipper started.

"Shhh! Just relax." Pacifica whispered as she led Dipper to his bed, stripping off Mabel's sweater, revealing the colorfully bedazzled bra underneath. "Your twin sister is going to take good care of you."

"Pacifica!" was all Dipper could say before being pushed on the bed and immediately ravaged by the young woman in his sister's overstimulated body.

"No more talking!" Pacifica commanded. "After all this, I am so worked up, I need to have it, and I need it now!"

Her hands pulled at his clothes, tossing them every which way as her lips trailed kisses up and down his chest. Dipper's heart began to race. His breathing became heavy. He honestly could not believe the sight before him. Sure, he knew that behind those big, doe eyes, it was Pacifica pulling the strings, but it was Mabel's body pressed firmly against his. It was Mabel's hands unbuttoning his pants and pulling them to the floor. It was Mabel's lips and tongue trailing kisses down his chest, across his stomach, all the way down to the tip of his–

"OH DEAR GOD!" Dipper exclaimed as he was enveloped in a warm and wet embrace. His eyes rolled back in pure delight as his hands gripped the bed sheets for support.

"Oh . . . OH! . . . MABEL!" He shouted. "Sorry! I mean–"

"No, it's okay," Pacifica gasped, coming up for air. "Call me by your sister's name! It's such a fucking turn on!"

Dipper tried to protest, but was instantly made silent as Pacifica returned to the job at hand, stimulating every nerve ending in the young man's member, sending bolts of pure electricity throughout his body, and flooding his mind with enough endorphins to leave the teenaged genius in a complete stupor, to the point that he could only manage the same phrase, over and over.

"Oh Mabel . . . Oh Mabel! . . . OH MABEL! . . . OH!"

Suddenly, on the other side of the room, Dipper could hear a familiar voice moaning almost as loud as he was. Out of the corner of his eye, the young man spotted the source of the noise. There, on Mabel's bed, he saw Pacifica, or rather, Pacifica's body; half naked, breasts exposed, hands thrust down into her panties, watching the scene before her unfold.

"Oh yes . . . Oh yes! . . . More . . . MORE!" Mabel shouted as she furiously pleasured herself from across the room, one hand gripping her breast as the other stimulated her throbbing loins. "Keep going! . . . Do it! . . . My God, this is so kinky! I don't know how much longer I can last!"

Pacifica perked her head up and laughed. "Looks like she's enjoying herself." The young heiress turned back to Dipper. "Time to give her a real show."

With that, Pacifica tossed away her final articles of clothing, the bedazzled bra and her now thoroughly soaked panties. The two lovers were completely bare. Dipper laid there, hard and erect as Pacifica towered over him, eager and ready while still in Mabel's body.

"Oh, wait!" Pacifica paused. "Do you have a condom?"

Dipper froze. In his lust, he completely forgot about protection. After all, this was his sister's body. The last thing they wanted to do was risk–"

"It's fine," a voice from across the room called out. "You don't need it."

The two lovers did a double take. "Are you serious, Mabel?" Pacifica asked.

"Yeah. I'm on the pill." Mabel responded between moans, her hand still thrust down her pants. "Besides . . . I want to see you do it raw!"

Pacifica turned back to Dipper. "Well, you heard her, Pine Tree." The young woman positioned herself over Dipper's throbbing member.

"Ready to head into the unknown?" Pacifica asked.

"Nope." Dipper replied. "Let's do it."

With that, Mabel's body came thrusting down onto Dipper's manhood.

The young man couldn't speak. He couldn't move. He was completely engulfed in a pleasure so intense, it paralyzed him, and the knowledge that he was receiving that pleasure from his sister's body only heightened the experience, taking him to peaks of euphoria he did not think were possible.

For Pacifica, unfortunately, it was a different experience.

"Fuck! That hurt!" The young woman shouted.

"What?" Dipper froze. "Pacifica, are you okay?"

"Yeah, I–" Pacifica winced. "Hold on, I just . . . jeez, this hasn't hurt like this since . . . wait a minute . . ."

Pacifica turned to Mabel, staring daggers. "Mabel, you bitch! Are you a virgin?"

Mabel smiled as she tried to avoid eye contact. "No . . . well, not exactly."

"What does that mean; not exactly?"

"Well, I have done it with you, haven't I?" Mabel laughed, "and I have other . . . experience."

Does any of that . . . experience involve a penis going inside your vagina?" Pacifica asked, "or maybe a dildo, or, hell, ANYTHING!?"

"Well . . . No." Mabel said flatly.

"God damn it, Mabel!" The heiress fumed. "Were you just using me as a stand-in to punch your v-card?"

"No! I really want to help my brother, and I really think this is the best way to do it." Mabel cried out. "I mean, yeah, the thought did cross my mind, but it wasn't the main reason I–"

"Mabel, shut up!" Pacifica sighed as she adjusted to Dipper's girth.

"Pacifica, are you okay?" Dipper asked. "I'm sorry if I–"

"It's okay. You did nothing wrong." Pacifica smiled before glaring back at Mabel.

"I'll deal with you later!"

Slowly, but surely, Pacifica became used to Dipper's size. As she began to bounce up and down on his shaft, a rush of pleasure flooded her mind. Within moments, her thrusts became longer, deeper and harder, as the two drew more and more pleasure from their quivering, sweat-soaked bodies. Soon, the pair were moaning in euphoria, with each movement taking them ever higher, their pleasure growing and growing to the point where they were teetering on the very edge of sanity.

"Oh God. Oh God! YES!" Pacifica exclaimed. "Harder! Faster! MORE!"

"Oh jeez. OH JEEZ! Pacifica! Pacifica, I'm gonna–"

"Do it. Do it, Dipper! Cum inside me." Pacifica shouted.

"CUM INSIDE YOUR SISTER!"

That was all Dipper needed as the realization of what he was about to do overpowered his senses. Any semblance of restraint was gone as he released deep into his sister's flailing body, triggering Pacifica's own climax in the process. The heiress threw her, or rather Mabel's head back as her body went ridged, holding on for dear life as the flood gates burst open. Mabel, for her part, could only sit and watch as the sight of her own body enthralled in orgasmic bliss finally set her off, and she roared in pleasure from across the room.

Just as quickly as it began, it was over. The three lovers lied spent upon the twin beds. Pacifica suddenly went slack with exhaustion as she collapsed onto Dipper, who could barely keep his own eyes open.

"Was it everything you hoped for?" Pacifica whispered.

Dipper could barely stay conscious, but with his last bit of strength, he replied.

"All of that . . . and more."

With that, Dipper shut his eyes and went to sleep.


	3. Chapter 3

Chapter 3

Dipper woke up in a daze an hour later, sweat from the summer heat and the day's earlier events dotting his forehead. Yet, despite the workout he had just received, the young man felt a familiar stirring beneath his sheets, and he wasn't the only one who took notice.

"Mmmm, looks like someone is finally up. Oh, and you're awake, too!"

Dipper leaned over to find a familiar brunette staring back at him with a devious smirk on her face.

"Mabel?" asked Dipper.

The young lady paused for just a moment, then smiled.

"Hmm . . . Guess again, Dipper."

Slowly, the young man began to recall the day's events.

"Pacifica? You haven't switched back yet? Where's Mabel?"

"Calm down, Dipper." She laughed before clearing her throat. "Mabel . . . is fine."

She paused, as if lost for words. "You see . . . um . . . your sister felt the sudden need to . . . to go down to the store and get some snacks and sodas for us!"

"But, why?" asked Dipper. "We have plenty of snacks in the shack."

"Oh, well . . ." She stammered before recovering. "I think she just wanted to cause some mischief by prancing around in my body."

"Really?"

"Well, of course." She laughed. "You know Mabel, always causing trouble, always doing things she knows she . . . really shouldn't."

"And you're okay with that?" Dipper asked.

The young woman smiled. "Well, if it means I get some alone time with you, so be it."

Seductively, she sauntered onto the bed, crawling up until she was face to face with her beloved.

"Um . . . Pacifica?"

"Shh . . . Quickly, Dipper, before she gets back, let's . . . let's just do it!" She exclaimed. "Do it again, I mean, before your sister gets back."

Dipper froze. "Pacifica . . . Pacifica, I don't know–"

"Oh! What's the matter? Does your . . . BIG dipper need a little more . . . convincing!?" She said, trailing kisses from his neck, down his chest, and even lower still.

"Oh . . . Pacifica . . ."

"I thought I told you before," she said, her lips hovering just over the tip of his erect member. "Call me Mabel."

With that, the young lady engulfed his hard, throbbing member into her warm, wet mouth, sending a surge of heat and electricity through Dipper's body and into his brain. Dipper's spine stiffened, then went slack as feelings of intense pleasure washed over him.

"Oh! Pacifica . . ." he mouthed before correcting himself.

"Sorry . . . I mean . . . Oh, Mabel!"

He had never felt anything like this before. Sure, he had been sucked off by Pacifica plenty of times in the past, even while in Mabel's body, but this time was . . . different. It was as if she had become an entirely different person, filled with passion and ferocity, and so much wild abandonment, it overwhelmed Dipper's senses to the point that he nearly lost all control.

"Pacifica . . . Mabel . . . Pacifica . . . Wait! Stop!" Dipper shouted, causing the young woman to perk her head up in surprise."

"If you keep going like that," Dipper gasped, "I won't last another minute."

She smiled another devilish little smile. "Oh, is your sister's mouth suddenly too much for you?"

"Don't be gross, Pacifica!" Dipper scoffed.

She just laid there, chuckling to herself, before slowly moving up the length of his body.

"Well then, I guess we should cut to the chase, huh, Dipper?"

"Wait, What?" Dipper muttered as his lover positioned herself just inches above his throbbing manhood.

"Oh, this is going to be so good!" The young lady exclaimed as she slowly lowered her body.

"Wait! She could back any minute!" Dipper panicked.

"Exactly. That's why I . . . we need to do it while we still have some time."

"Pacifica–"

"I told you," she yelled as her pussy enveloped his cock, "call me . . . Oh God!" She cried as she rammed her body all the way to the hilt."

" . . . Call me Mabel."

Dipper tossed his head back in ecstasy as his lover moaned, taking his hands in hers and forcing them onto her heaving breasts.

"Squeeze them, Dipper!" She shouted. "Squeeze them hard!"

Dipper was happy to oblige, carefully kneading her soft breasts as her body bounced on his throbbing manhood.

"Harder!" She screamed. "Harder, damn it! Pinch my nipples!"

Dipper's hands moved over the young woman's pink and perky nipples, pinching and pulling them hard as a long, drawn out moan escaped from deep inside her body.

"THAT'S IT! That's what I like! Oh God! I've been waiting for this for so long!" She gasped. "I'm gonna cum. I'm gonna cum, Dipper! You're going to make me cum!"

Dipper was at his wits end. "Oh Pacif– I mean Mabel," he said, correcting himself. "I'm going to cum, too."

"Do it, Dipper! Cum in me!" She screamed, as her orgasm erupted.

"CUM INSIDE ME!"

"Oh God! Oh . . . Pacifica! . . . OH MABEL!"

With that, Dipper exploded inside his sister's body once more as his lover rode his orgasm to a second climax. Her eyes rolled back into their sockets as her body convulsed erratically on top of his, moaning with each involuntary spasm. Finally, exhausted from multiple, cascading orgasms, the young lady collapsed upon her lover's body; their tired, sweat-soaked forms melting into the mattress as they both struggled for breath.

"Oh, Pacifica!" Dipper moaned. "That was . . . That was amazing!"

"Yeah," She smiled. "I got to agree with you there. God, I love riding your big dipper!"

Dipper rolled his eyes and laughed. "Enough with the big dipper jokes already. Jeez!"

"Well, what do you expect with a nickname like Dipper?" She laughed.

"At least it's just a nickname." Dipper chuckled. "What kind of name is Pacifica Northwest, anyway?"

"Well, it's better than Mason." She smiled.

Dipper froze at those words. "What did you say?"

"Mason." She replied. "It's your real name, dummy!"

"How do you . . . I've never told you that!" said Dipper. "Hardly anyone knows my real name, except . . ."

"MABEL!" a voice shouted from just beyond the bedroom door. "I'm back, and I got the stuff you wanted. I still don't know why you made me go to the store across town. It took me forever. Is Dipper awake, yet?"

Pacifica walked through the door and saw the naked, sweat-soaked bodies of the Pines twins laying on the bed.

"Oh! Looks like you two have been busy!" The Northwest heiress exclaimed. "I can't believe you did it without me!"

Dipper's face went white with shock. "Wait! Pacifica? I thought . . ." Dipper looked back at the woman laying on his bed. "You mean, all this time, you were . . . you were . . .?"

"Whoops!" said Mabel. "Busted!"


	4. Chapter 4

Chapter 4

"YOU'RE MABEL!" Dipper exclaimed, pointing at his sister.

"Ye– Yeah . . . Sorry." Mabel winced, her face flushed with guilt.

"I can't believe this! How could you lie to me like this?"

"I didn't lie!" Mabel replied. "I just . . . Okay, I lied, but I had to, Bro! You were just so nervous about . . . everything. I figured, if you could do me while still thinking I was Pacifica, you would loosen up and be able to, you know, preform."

"And? Did he preform?" Pacifica asked, smirking.

"Oh, he preformed, alright. We're talking an Oscar-worthy performance!"

"Lucky girl!" Pacifica laughed. "To think I missed it getting your damn sodas."

"Speaking of, could you give me one?" asked Mabel. "I am seriously dehydrated."

"That's Enough!" Dipper shouted. Mabel and Pacifica both froze as he shook. "I still haven't forgiven you for tricking me!"

"But Dipper, I didn't mean to–"

"He's right, Mabel."

"Pacifica?"

"Remember when I tried to trick you and Dipper by spiking your drinks?" asked the heiress. "It wasn't right for me to deceive you back then and it wasn't right for you to deceive your brother tonight. Even if it was with the best intentions, a lie is still a lie. You need to make this right."

"Pacifica . . ." Mabel sighed, realizing what had to be done. "You're right."

Mabel turned to her brother.

"Dipper, I'm sorry. It wasn't right for me to trick you like that. I love you, and the last thing I'd want to do is hurt you."

Dipper sighed. "Mabel . . . I–"

"Besides," Mabel smirked. "Didn't it feel absolutely amazing to cum inside of me like that?"

Dipper blushed with embarrassment. "Yeah . . . It was pretty great."

"And now that you know that you really came inside me, inside your sister; body, mind and soul, how do you feel?"

"I . . ." Dipper paused. How did he feel? Now that the shock had worn off, was he any worse off than where he was before? Did any of his fears or anxieties come to pass?

"I feel pretty good. I guess . . ."

"And look outside! Has the sky ripped open? Has the sun gone out? Is a triangle-shaped demon reeking havoc on the town?"

"No," Dipper sighed, "None of that is happening, Mabel."

"Right. So you had an amazing, passionate sexual experience with your sister, and nothing bad happened?"

"I . . . Yeah, I guess you're right." Dipper smiled.

"And, and this is the important part," Mabel said as she sauntered up to her brother, "If I were to say that I wanted to do all of that again, would you be willing?

Dipper's body went ridged, in more ways than one.

"Absolutely!" Dipper exclaimed.

"Good," said Mabel, "because once I get a few sodas and some candy in me, we are gonna go all night!"

"Not without me!" cried Pacifica. "You had your turn. Now, it's mine!"

A few Pitt Colas and a handful of sweets later, and the three sugar-high teens were making love once again. Dipper kept himself busy as the two women passionately made out with one another. Hands and tongues probed every inch of their young bodies as Dipper thrusted away with his manhood, splitting his time between Pacifica and his sister, his fears and anxieties dropping at the waist-side.

"Oh God!" Dipper moaned.

"This is so nasty!" Pacifica cried out.

"Oh . . . Wow! Bro, I love your dick!" Mabel squealed as Dipper thrusted extra hard into her quivering pussy.

Soon, the confines of the bed were too small for the sex-starved lovers as the three teens rolled onto the floor, a mass of limbs that delighted in stroking, pinching, petting and thrusting into one another to the point of ecstasy.

"I'm gonna cum!" Mabel squealed.

"Me too, sis." Dipper cried. "I'm so close."

"Let's all do it together!" Pacifica yelled. "I'm almost there!"

The three pushed each other over the edge and allowed themselves to be enveloped in pure, orgasmic bliss. Their bodies tingled with excitement as they were overcome with earth-shattering orgasms, and everything went white.

Although, that might have been because they accidentally rolled onto the body-switching rug.

When the smoke cleared and the dust settled, the trio looked around the room at one another.

"What happened?" said Mabel, coming from Pacifica's body.

"I think . . . I think we all switched bodies, again." Dipper stuttered while trapped inside Mabel.

"Okay, so if I'm actually Mabel . . . "

"And I'm really Dipper, that means . . ."

"Oh! This is interesting." Pacifica smirked from inside Dipper's body, standing tall and stroking a very erect penis.

"This gives me a very interesting idea."

"Me too!" Mabel shouted as she turned to her brother.

"I'll go get the Hot Wheels tracks!"

. . . . .

A month rolled by, and Dipper, Mabel and Pacifica soon settled into their new home on the edge of town. Friends and family were happy to see the trio out on their own, but they were a little suspicious of their relationship, especially since the house they decided on only had a single, extra-large bedroom with a single, extra-large bed . . . and what was with that weird, blue rug?

Then again, this is Gravity Falls. This town is used to its share of weirdness.

The End


End file.
